Gas generator



F. C. GREENE GAS GENERATOR Feb. 20, 1934.

Filed Aug. 5l, 1928 2 Sheets-Sheet l l N VEN TOR. jre C. ./'eefe A TTORN Y6,

F. C. GREEN E Feb. 20, 1934.

GAS GENERATR Filed Aug, 3l, 1928 2 Sheets-Sheet 2 mms/TOR. fran/ C' @7196716 Patented Feb. 20, 1934 UNITED STATES l I l 1,947,590

PATENr OFFICE 8 Claims.

The present invention relates, as indicated, to a gas generator. The primary object of the invention is to provide a unit in which coal or other fuel can be economically transformed into fuel gas which can be immediately used or which can be stored for future use. A further object is to provide a unit of reasonable size which shall be capable of producing very large volumes of gas for steam generation, open hearth furnace operation, glass melting and similar operations. To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims.

The annexed drawings and the following description set forth in detail certain mechanism embodying the invention, such disclosed means constituting, however, but one of various mechanical forms in which the principle of the invention may be used.

In said annexed drawings:

Fig. 1 is a segmental transverse section of a gas generator according to the present invention and Fig. 2 is a section taken on the line It is well known that the art of fuel combustion has not kept step with modern heat and energy requirements. As an example, there are in use at present, electrical generators rated as high as 165,000 kw. Such generators themselves are not of such huge size as to be unreasonable,

but the boiler installation for such a generator, using known apparatus, is unreasonably large. The installation disclosed in the accompanying drawings has a base diameter of fifty feet and is ,capable of gasifying some 720 tons of coal per vday with a resultant gas out-put, converted to power, of 60,000 kw.

Referring now more particularly to the drawings, it will be seen that the generator comprises a base mounting a substantially hemispherical dome 11 provided on its inner surface with a wall 12 of heat reflecting material so placed las to make the interior surface of the generator substantially frusto-conical. The interior of said generator is connected by a plurality of radially disposed olf-take ducts 13 with yan annular gas oir-take tube 14 surrounding said generator body proper. The ducts 13 are separated by Aarch-,ways 15 which, as will later appear, act Aalsoas hold-backs for the mass of fuel in the generator. The oor 16 of the off-take tube 14 slopes downwardly from the position illustrated VAto a level substantially that of the upper surface of the supporting floor 10 at a point approximately 180 removed from that shown, thus increaslng the cross-sectional area of the tube inaccordance with the number of ducts entering Athe same, it being understood that the off-take stack in its open upper end and said conduit hasits lower end mounted in an aperture 18 in a hearth 19 secured in said furnace whereby such fuel, indicated at 20, is delivered by said tube" 17, against a baffle plate y21.

Within said generator there is mounted a frusto-conical rotor 22, the lower end voffwhich comprises a feed trough 23 into which `theb'a'iile plate 2l extends. Said plate is formedlwithfone or more apertures 24 which permit the passage of the fuel into the trough 23. The rotor22 is provided with an annular rail 25 securedto its lowermost portion and Supported uponaplurality of rollers 26 mounted in bearings .2`7`1`Ion the base plate 10, Vand said trough formedon its one under surface with a plurality `of teeth 28 meshing with a bevelled pinion 29 mounted on a shaft 30 adapted to be rotated by a, motor (not shown). An air inlet conduit 31 is adapted to have its outer end v31 connected tov the disoharge'feid 'f a blower (not shown), and said conduit .extends into said generator and has its inner, end .32

turned upwardly to extend into the basefaiof an evass tube 34, having its upper end 35L 'flared as shown. Preferably,`a steam nozzle BGadaptd to .be controlled by a Valve 37 extends through 'aperture`38 into the upturned end 32 `of said conduit 3 1.

It will be noted that the flared end 35 of the evass tube 34 extends to aV point slightly-,above the open upperend of the rotor'22fand thatsaid end is located adjacent the opening 40 centrally formed in the top of the `dome 11. Incidentally, said opening is preferably surrounded by a Aguard rail 41. .A flared deflector 42 is secured inwsaid open flared end 35 `of the tube :B4-and has its peripheral edge spaced slightly fromthe edge of said tube. Guide iingers 43 secured to said tube slidably center the tube in the open end- 39o-f the rotor, and means 44 (diagrammatically illustrated in the drawings) are provided for shifting said tube vertically for a purpose llater to 'be described. i A ,The rotor 22 is formed orprovided onk its external surface with screw flights 45, and a series lof apertures 46 .is formed' in said rotor ,immediately vbeneath each ofsaid flights. Presuming that the furnace is in operation` and is malging combustible gas, a wall of fuel, such as coal, is built up in said furnace. -Said wall comprises an outer incandescent layer 47, the surface of which is. substantially parallel with the inner surface of the lining 12; a-layer 49 of plastic fuel immediately within or below said layer 47; a layer 500i wet fuel; and a layer 51 of `ldry fuel in contact lwith the rotor. While I have shown the Vbeing carried off from the generator.

boundaries between said layers as quite definite, it should be understood that this is for the purpose of clarity of illustration only, and that such boundaries are not at all so definite. The four zones are dened by critical temperatures, the Zone or layer 47 having a temperature varying between 3500 and 3000 F.; the layer 49 varying between 900 and 400; the layer 5i) having a ternperature of approximately 212 and the layer 51 having a temperature of about 60 to 80.

The air for supporting partial combustion in the generator is in part supplied by a blower (not shown) through the conduit 3l, to the evass tube 34 and is deflected by the deflector 42 so that it issues with high velocity around the top of the evass tube as a primary air blast indicated by the numeral 55. The force of this blast induces side currents of air 54 and 55, the former being primary inside air drawn from the interior 53 of the structure, and the latter being primary outside air drawn through the top orice of the dome by the suction of the primary air blast 55.

Ythe space 52 tothe interior 53 of theV structure.

This current passes from the space 53 between the open upper end 39 of the rotor 22 and the edge of the flared end 35 of the tube 34.

rIhe blower (not shown) thus induces a draft downwardly over the whole surface of the incandescent layer 47 of the fuel wall and thus through the ducts i3 to the off-take tube i4. The air is supplied in quantities insufficient to effect complete oxidation of the fuel, and as a consequence the carbon content of the gas which enters the tube 14 is very largely in the form of CO. The rubbing effect of the blast on the Vsurface of the layer 47 disengages the particles of fly-ash remaining after combustion and such particles are entrained in the gas stream, thus This wiping or abrasive action of the air blast assures the removal of all ash from the generator and thus eliminates the possibility of clinkers forming in the generator.

As the fuel is removed from the layer 4'. by combustion and by abrasion of the air blast, its place is taken by fuel which has passed through the Zones 51, and 49. As the shaft 30 rotates to drive the rotor 22 through the pinion 29 and the teeth 28, the fuel 2O is picked up from the trough 23 by screw nights 45 and is carried upn wardly along these flights between the rotor 22 and the baffle plate 2i to the level of the hearth 18. The fuel wall itself then` acts as the retarder for the fresh fuel to permit the flights 45 to carry -the same upwardly, and fresh fuel is thus carried upwardly toward the tcp of the rotor. As the fuel wall retards the fresh fuel on the flights 45, it causes an extrusion of such fresh fuel out- Wardly from the rotor, and such extrusion must, of course, be communicated to the fuel in the remaining three zones of the wall. Thus the nights 45 act notonly to elevate the fuel, but

changed into a highly reactive char, and it is in this condition that it iinaliy reaches the incandescent teinperature and reaches the region where it can come into contact with the combustion-supporting gas of the air blast. Furthermore, as the fuel is forced outwardly from the rotor, it will be obvious that the circumference of the wall increases. rIhis necessarily causes crenellations in the fuel surface to increase very materially the area with which the combustionsupporting gas can come into contact.

A very important feature of the present invention is the fact that, through the method of gas generation employed, it is possible to extract from the fuel many of the valuable light distillates thereof. In this connection, it will be noted that, whereas all fuel combustion devices with which I have previously been acquainted have brought the combustion-supporting gas through the fuel bed-through the cold fuel, through the hot fuel, and into contact with the incandescent fuelmaccording to the present invention, no combustion-supporting gas is Vdrawn through the fuel wall, but all cf such gas simply wipes along the surface of the incandescent fuel. As a matter of fact, it would be impossible to draw any gas from the surface of the rotor through the fuel wall, since it has been found that the plastic coal in the layer 49 forms a more or less fiuid wall quite impervious to gases and vapors. It is by taking advantage of this quality of the layer 49 that I have been. enabled to recover the light distillates of the fuel.

The apertures 45 in the rotor 22 have previously been mentioned. An annular chamber 57 is supported within the rotor and is always in communication with said apertures. The lower end of said chamber communicates with the interior of an annular reservoir 58 having an open lip 59 in which may preferably be inserted tubes 60 for withdrawing the liquid distiilates from said reservoir. Preferably, the 'interior of the reservoir 58 is maintained at a temperature of about 2l2 F., so that all distillates which are liquid at such temperature may be withdrawn through the tubes 60, and a conduit 6l has its one end in communication with the upper portion of reservoir and its other end connected to the interior of the evasse tube 34. Such conduit 61 thereby performs two functions, viz., it reduces the pressure within the reservoir 58, thus causing the distillates of the fuel to be drawn through the apertures 46 and into said reservoir, and it provides passage through which such distillates as are vaporous or gaseous at the temperature of the reservoir may be drawn into the evasse tube and carried with the air blast into contact with the incandescent layer 47 and so into the gas eff-take tube 14. The conduit 61 is preferably provided with a clean-out opening closed by hinged cover 62. I prefer to provide a scrubber 53 in connection with the reservoir 58 for cleaning the liquid distillates collected therein.

Preferably the entire installation is encased within a slightly sloping mound 64 of loam of weil selected rooty material.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the mechanism herein disclosed, provided the means stated by any of the following claims cr the equivalent of such stated means be employed.

I therefore particularly point out and distinctly claim as my invention:

1. In a gas generator, a structure substantially conical as to its inner surface, a frusto-conical rotor in said structure, screw flights carried by said rotor on its outer surface, said rotor being formed with a series of apertures immediately below each of said flights, means for feeding fuel to the base of said ilighted rotor, means to cause rotation of said rotor whereby a frusto-conical fuel wall spaced from the walls of said structure is built up, an annular chamber within said rotor in communication with said apertures, a reservoir connected to said chamber and adapted to collect the lighter distillates of said fuel, means for causing a draft of air to sweep downwardly over said fuel wall and means connecting said lastnamed means with said reservoir.

2. In a gas generator, a structure substantially conical as to its inner surface, means for forming Within said structure a substantially conical wall of incandescent fuel, an off-take conduit, and means including an evass tube opening into said structure above the upper end of said wall for causing a draft of air to sweep downwardly over the surface of said wall and into said conduit.

3. In a gas generator, a structure substantially conical as to its inner surface, a frusto-conical rotor in said structure, screw flights carried by said rotor on its outer surface, means for feeding fuel to the base of said flighted rotor, means to cause rotation of said rotor whereby a frustoconical fuel wall spaced from the walls of said structure is built up, and means including an evass tube opening into said structure above the upper end of said wall for causing a draft of air to sweep downwardly over the surface of said wall.

4. In a gas generator, a structure substantially conical as to its inner surface, a frusto-conical rotor in said structure, screw flights carried by said rotor on its outer surface, said rotor being formed with a series of apertures immediately below each of said flights, means for feeding fuel to the base of said flighted rotor, means to cause rotation of said rotor whereby a frusto-conical fuel wall spaced from the walls of said structure is built up, an annular chamber within said rotor in communication with said apertures,- a reservoir connected to said chamber and adapted to collect the lighter distillates of said fuel, means including an evass tube opening into said structure above the upper end of said wall for causing a draft of air to sweep downwardly over the surface of said wall, and a tubular member opening into the upper portion of said reservoir and into said evass tube.

5. In a gas generator, a structure substantially conical as to its inner surface and open at its tcp, a frusto-conical rotor in said structure, screw flights carried by said rotor on its outer surface, means for feeding fuel to the base of said ilighted rotor, means to cause rotation of said rotor whereby a frusto-conical fuel wall spaced from the walls of said structure is built up, an evass tube vertically disposed substantially centrally of said structure and having its upper flared end located adjacent the open top of said structure and slightly spaced from the open upper end of said rotor, means for forcing air into the lower end of said evass tube, and a flared deilector secured in said flared end and adapted to direct such air do l wardly over the surface of said fuel wall.

6. In a gas generator, a structure substantially conical as to its inner surface and open at its top, an olf-take conduit communicating with the interior of said structure, a frusta-conical rotor in said structure, screw flights carried by said rotor on its outerv surface, means for feeding fuel to the base of said flighted rotor, means to cause rotation of said rotor whereby a frusto-conical fuel wall spaced from the walls of said structure is built up, an evass tube vertically disposed substantially centrally of said structure and having its upper flared end located adjacent the open top of said structure and slightly spaced from the open upper end of said rotor, means for forcing air into the lower end of said evass tube, means for admitting air to the interior of said rotor, and a flared deilector secured in the flared end of said evass tube, whereby a draft compounded of air forced into the lower end of said evass tube, air admitted to said structure through the open top thereof, and air admitted to the interior of said rotor through said last-named means is directed downwardly over the surface of said fuel wall to said off-take conduit.

7. In a gas generator, a structure substantially conical as to its inner surface and open at its top, an off-take conduit communicating with the interior of said structure, a frusta-conical rotor in said furnace, screw flights carried by said rotor on its outer surface, means for feeding fuel to the base of said ilighted rotor, means to cause rotation of said rotor whereby a frusto-conical fuel wall spaced from the walls of said structure is built up, an evass tube vertically disposed substantially centrally of said structure and having its upper flared end located adjacent the open top of said structure and slightly spaced from the open upper end of said rotor, means for forcing air into the lower end of said evass tube, means for admitting air to the interior of said rotor, a flared deflector secured in the flared end of said evass tube, whereby a draft compounded of air forced into the lower end of said evass tube, air admitted to said structure through the open top thereof, and air admitted to the interior of said rotor through said last-named means is directed downwardly over the surface of said fuel wall to said off-take conduit, and means for shifting said evass tube vertlcally to vary the composition of said draft.

8. A gas generator comprising a structure having an opening at its tcp, a gas-oi-take conduit having a communication with the interior of said structure, an annular hearth mounted in said furnace, a rotor mounted in said structure and formed with a feed trough extending beneath said hearth, means for feeding granular fuel to said feed trough, screw flights on said rotor and adapted to carry said fuel upwardly and to form the same into a substantially conical wall resting on said hearth and on said rotor but spaced from the lateral walls of said structure, an evass tube vertically disposed in said structure and laterally enclosed by said rotor, the upper end of said evass tube extending slightly beyond the open upper end of said rotor and being located adjacent the open top of said structure, a pipe adapted to be connected to a source of air under pressure said pipe extending into said structure and being curved upwardly to extend into the bottom of said evass tube, a second pipe adapted to be connected to a source of steam under pressure and projecting into the upwardly extending portion of said first pipe, an open-ended conduit opening into the space dened by said rotor and extending to the exterior of said structure, a flared deflector secured in the upper flared end of said evass tube, and means for driving said rotor.

FRANK C. GREENE. 

